docs: def cortex_cmap_plot_2D(the_map, zs, cmap, vmin=None, vmax=None, axes=None, triangulation=None):
      '''
      cortex_cmap_plot_2D(map, zs, cmap, axes) plots the given cortical map values zs on the given
        axes using the given given color map and yields the resulting polygon collection object.
      cortex_cmap_plot_2D(map, zs, cmap) uses matplotlib.pyplot.gca() for the axes.
  
      The following options may be passed:
        * triangulation (None) may specify the triangularion object for the mesh if it has already
          been created; otherwise it is generated fresh.
        * axes (None) specify the axes on which to plot; if None, then matplotlib.pyplot.gca() is
          used. If Ellipsis, then a tuple (triangulation, z, cmap) is returned; to recreate the plot,
          one would call:
            axes.tripcolor(triangulation, z, cmap, shading='gouraud', vmin=vmin, vmax=vmax)
        * vmin (default: None) specifies the minimum value for scaling the property when one is passed
          as the color option. None means to use the min value of the property.
        * vmax (default: None) specifies the maximum value for scaling the property when one is passed
          as the color option. None means to use the max value of the property.
      '''
      if triangulation is None:
          triangulation = matplotlib.tri.Triangulation(the_map.coordinates[0], the_map.coordinates[1],
                                                       triangles=the_map.tess.indexed_faces.T)
      if axes is Ellipsis: return (triangulation, zs, cmap)
      return axes.tripcolor(triangulation, zs, cmap=cmap, shading='gouraud', vmin=vmin, vmax=vmax)